湖南怀化地区96.7城市特大洪涝灾害成因分析

湖南省怀化地区地形以山地为主，该地区１９９６年７月发生了城市特大洪涝灾害，本文概述了该地区９６．７城市洪涝灾情，并以区域灾害系统论为指导，从孕灾环境、致害因子、承灾能力和人类活动的不利影响等方面，对这次灾害的成因进行了分析，认为其主要成因是：（１）易洪涝的山丘区环境；（２）９６．７降雨强度大、覆盖面广、持续时间长的异常雨情和高洪峰水位、流量的异常水情；（３）城市防洪标准低、水利水电工程防洪效益差和抗洪害意识不强等原因造成的城市防洪能力低；（４）砍伐森林、人为侵占河道和大型水库超常规蓄水等人类活动造成的不利影响。

ANALYSIS ON FORMATION FACTORS OF THE SEVERE URBAN FLOOD AND WATERLOGGING IN JULY,1996 IN HUAIHUA,HUNAN

A severe urban flood and waterlogging occurred in the mainly mountainous Huaihua region,Hunan province in July,1996.Guided by systematic theory of regional disaster,this paper analyses the formation factors of the disaster in term of environmental liability,inducements,abilities of withstanding disasters and the detrimental effects of human activities.The main causes of the disaster are summarized as follows:(1)the mountain area environment prone to floods;(2) the abnormal conditions of both the long term intense rainfall covering wide areas and the water regimen of high flood level and peak discharge in July 1996;(3) the inferior capacity of urban flood control caused by inadequate urban flood preventing standard,the bad performance of water conservancy works and the poor flood preventing consciousness;(4) the detrimental effects of human activities such as felling of trees, artificial seizure of river course and an excess of water retaining in big reservoir.